Land hermit crabs make good pets, but they are not as easy to care for as some people think, especially since strict humidity and temperature control are required. Before getting a hermit crab, you should learn about hermit crabs in general, about land hermit crabs, and about the requirements of your specific species (temperature, relative humidity, and shells). Have your habitat set up and ready before you bring home your new crabs.

Most land hermit crab owners in the United States have Caribbean hermit crabs (also commonly known as Purple Pinchers), which can live to be over 30 years old (over 40 years in exceptional cases). "Jumbo" Purple Pinchers are thought to already be over 20 years old. This species requires a relative humidity level between 70% and 78%, and prefers a temperature of 24 °C (75 °F).

The name "hermit crab" is a misnomer. Land hermit crabs are very social creatures who live in colonies of 100 or more in the wild and they do not fare well as solitary pets. At times they communicate with each other via chirping sounds known as stridulation.

Since these animals spend long periods (weeks or months) molting below ground, keeping them in groups of three or more will help to keep these pets from being lonely or depressed. The stress from being alone can have serious health effects.

Land hermit crabs breathe using modified gills rather than lungs. Low relative humidity (below 70%) makes breathing difficult for them and can seriously damage their gills. An hour in normal household humidity (~50%) is not a serious problem, but longer periods are. Frequent misting (with a fine spray) is advisable while your land hermit crab is outside the habitat.

Post-purchase stress (PPS) death "is death as a result of a crab being deprived of the resources he needs to adapt metabolically to conditional changes in his environment (humidity/temperature)." (Coenobita Research)

If a land hermit crab is purchased from a situation where the crab has suffered from improper humidity and/or temperature conditions for a long enough period of time (even as little as a few hours with very low humidity), the crab will be suffering from severe stress. Suddenly putting that crab into good conditions can result in death if the crab is already too weak to make a quick adjustment.

See the Coenobita PPS web page for up-to-date instructions on how to deal with PPS. A gradual adjustment of humidity and temperature is required. The details of treatment are the subject of ongoing research.

In order to grow, a hermit crab must molt. Molting is a strenuous, hazardous, and potentially lethal process for a crab. A molt is the ultimate test of whether the crab is healthy and well nourished, and of whether the owner has provided a good environment (including calcium sources and salt water).

Land hermit crabs normally bury themselves and form an underground cave in which to molt; therein, extended darkness triggers the secretion of a molting hormone called ecdysone. The formation of this cave requires a moist, packable substrate. In captivity, the habitat's substrate needs to be at least twice as deep as your largest hermit crab to facilitate tunneling and digging.

In the cave the hermit crab uses stored water and salts to generate enough pressure to crack open its exoskeleton. It lives off of stored nutrients, plus the old exoskeleton, while the new exoskeleton hardens sufficiently. Any missing limbs are partially or fully regenerated. The molting cave protects the crab and the nutrients in the shed exoskeleton from being eaten by other crabs.

In an environment that is not conducive to a molt, the crab's system will secrete an anti-molting hormone. Nature provides this hormone as a short-term solution to adverse conditions. The full health consequences of a long-term molting delay are unknown, but extended molting delay is not a normal part of a crab's life cycle and may decrease the chances of a successful molt.

CAUTION: Never dig up a hermit crab who has buried itself! This is extremely stressful for the crab and could disrupt a molt, possibly killing it! There are some cases, however, in which you may need to dig them up, such as noticing the "death smell" (the strong, fishy smell associated with a dead hermit crab), one crab disturbing another, an outbreak of mold in the habitat, etc. As a general rule, you should not need to dig up hermit crabs.

CAUTION: A crab preparing to molt may go limp, appearing dead and lifeless. Even a dip in water may not elicit a reaction. Isolate limp crabs and hold off on the funeral until they smell fishy.

CrabWorks has a gallery of molting pictures. The habitat used was carefully designed so the molting cave could be temporarily exposed for pictures.

Without an appropriate substrate, eventually the hermit crab's only choice is to molt on the surface instead of underground.Underground cave is optional.They also enjoy huts.You usually can purchase huts where hermit crab are sold or you can make a hut.You need a coconut shell size of coconut matters how big the crab is.After you have cut the shell (over something to catch juice)scoop out all of fruit then cut small door like opening about 2in. wide and 2-3 in. tall.After this is done let set for 2-3 hours to dry from extra juice.

This is dangerous as other crabs may attack the defenseless, weakened crab or eat its shed exoskeleton and deprive it of nutrients. A cylinder with an opening at the top for air circulation can be used to isolate and protect the molting crab and its exoskeleton within the main habitat.

CAUTION: The exoskeleton of a surface molting crab may look like the dead body of a crab that has fallen out of its shell. Examine the "body" to see if it is hollow. Don't clean the shell without gently looking for a pale, soft crab huddled in the back of the shell.

HOWEVER: In one editor's personal experience, four of his or her hermit crabs perform nothing but surface molts despite having suitable substrate to molt in if they want to. All four crabs are very aggressive and have been seperated from other crabs. These crabs all surface molt inside hiding huts, and they do well regardless. He or she has witnessed the shedding of the exoskeleton and watched the crabs eat their exoskeletons over a three-to-four-day period. He or she usually puts black construction paper over the sides and front of the tank to keep it dark once he or she notices the crab has started to slow down, consume lots of food and water (both fresh dechlorinated and sea salt water) and stay close to their hiding huts. Usually he or she finds the shed exoskeleton a few days later. After a few weeks during which their new exoskeletons harden, they come out, ready to eat like crazy. So surface molting isn't always a deadly thing. He or she speculates that his or her hermit crabs regularly molt on the surface because they are kept isolated and know other crabs are not a threat.

Hermit crabs use land or marine snail shells as homes to protect their fragile bodies. To hermit crabs, shells are extremely important - as or more important than food. Hermit crabs may seek out a larger shell before or after molting, or sometimes a smaller, tighter shell instead, so it will be easier to dig out of the hole they make.

Each crab should have a wide selection of intact shells to choose among; at least four extras for each crab in the habitat. Offer shells the size of its current one, ones slightly larger, and ones slightly smaller. Shell size is measured using the diameter of the opening. A "larger" shell is 1/8" - 1/4" larger in diameter. A desired shell's opening or "mouth" is typically about the size of the large claw, plus about 2½–3 mm (1/10 in to 1/8 in) all around (more for larger crabs). Oblong openings of the right length might be too narrow, so be cautious when purchasing. Hermit crabs are generally drawn to shells with a smooth mother-of-pearl interior.

The more choices you provide, the less likely it is that one of your crabs will decide it wants to fight a neighbor for a shell already being worn. Shell fights can result in loss of limbs or death; a hermit crab will allow itself to be ripped apart rather than abandon its shell.

Avoid offering painted shells. Even if the paint is advertised as "non-toxic", that only means it is non-toxic to humans. A coat of clear varnish over the paint may not be safe either. Paint and varnish might be non-toxic to the touch, but toxic if consumed. Crabs will eventually chip paint and varnish off their shells, and the chips may be eaten. Paint or paint chips that get inside a shell are uncomfortable for the crab and could cause serious irritation. There are even cases in which hermit crabs forced into newly-painted shells with wet paint inside became stuck inside their shells, unable to move their limbs properly, retract inside or leave the shells. This condition usually ends in death unless the crab manages to loosen itself.

The "proper" shell for a given land hermit crab is whatever shell that individual finds comfortable. The crab's abdomen is partially shaped by previous shells and only it knows what is most suitable. A crab may try out a new shell and then decide that the change was a mistake, so don't quickly remove the original shell unless absolutely necessary (e.g. the shell is damaged or painted) unless you intend to clean and promptly return it to the habitat. Boil shells in chlorine-free water to clean and sterilize them (and let them cool) before offering them to your hermit crabs.

These species preferences listed are only guidelines, by no means precise rules. A crab of a species that usually prefers shells with circular openings may pick a shell with an oblong or D-shaped opening. A crab of a species that usually prefers shells with an elliptical or D-shaped opening may pick a shell with a circular opening.

Isolation tanks may be used for newly-acquired, sick, injured, or aggressive hermit crabs. New crabs can be treated for PPS symptoms and evaluated for illness and mites. Sick or injured crabs, especially those with shell disease, can be isolated from others. Aggressive crabs can be safely confined until they calm down.

If the main habitat is large enough, a smaller isolation tank with sick, injured, molting, or aggressive crabs can be set within the main tank so the crabs don't have to experience a change of environment. However, an isolation tank with new crabs should always be maintained separately to prevent the spread of mites or other pests to the main tank.

The use of an isolation tank for molting is not necessary, and arguably should be avoided altogether. Providing a proper substrate in the main habitat gives hermit crabs a safe, more natural way to molt and avoids the possibly harmful accumulation of the anti-molting hormone. To avoid stress, surface molting crabs should not be moved unless absolutely necessary.

If the new crab arrives in a fancy or painted shell, he or she may have been forced into that shell. This is done by methods that have been criticized as needlessly cruel, such as gassing crabs with nitrogen in the old shell, removing them from the old shell and placing them into the new shell, and reviving them with oxygen. Such a crab may be very stressed from the change and unhappy with its shell. Before purchase, ask

"How did you get the crab to change shells?" and, if it was not a voluntary switch,

"How long has the crab had to recover?"

Factor the answer into your buying decision.

For three to four weeks, a new crab should be allowed to live and eat in the isolation tank without competition from the established crabs. If necessary, the temperature and humidity can be gradually adjusted to match those of the main tank (see Post-purchase stress, above). A new crab may wish to bury itself to de-stress or molt. The owner must decide whether or not to immediately provide enough substrate for that. The crab may need more nourishment before molting and other hiding places can be provided.

If there are any concerns about the new crab's shell, be sure to provide a selection to tempt the new crab to change into a different shell. If no shell switch occurs and the crab is doing very well (eating, exploring, etc.), a new crab's natural shell can be cleaned to remove most organisms living on the shell. Barnacles can be removed with implements such as a dental pick. A toothbrush and sea salt can be used to scrub the shell. Do the cleaning a little at a time to avoid stressing the crab. The idea is to remove organisms, not to polish the shell.

To introduce new crabs to the main tank, dip each established crab briefly into the habitat's fresh water dish. Then, to transfer the smells of the colony, dip each new crab in the dish before putting him or her into the tank.

WATER: All water (H2O) for land hermit crabs must be free of any form of chlorine (including chloramine: How to remove chlorine from water. Chloramine removal products may leave toxic ammonia in the water. Read the product label carefully. If ammonia is not mentioned, use a different product.

FOOD: Food should be organic if at all possible to avoid exposing hermit crabs to pesticides. Try not to use commercial hermit crab foods sold from pet stores, as many of these products contain harmful chemical preservatives that have been linked to molt deformities. Any foods cooked for hermit crabs should be prepared in glass, ceramic, or stainless steel containers - not aluminum or Teflon. Kitchen fumes from the ordinary use of Teflon pans may be toxic. Fumes from overheated Teflon pans are definitely very toxic.

AIR:Insecticides, air fresheners, cleaning products, and many other chemicals are dangerous to hermit crabs. Anything sold in a spray or aerosol container could potentially harm the crabs - even hair spray, perfume, or air freshners. Think hard before putting any type of substance or fumes into the air and environment around your hermit crabs. Try to avoid cleaners, and anything else that'd leave a fume. If you can smell something, it is in the air.

Land hermit crab growth is very slow. Captive crabs have survived numerous molts in the wild to become large enough to be captured and sold as pets, but many of them fail to survive even one molt in their new homes due to some combination of

post-purchase stress

gills damaged by low humidity and/or chlorinated water

improper temperature

unsuccessful molting

lack of a proper substrate

molting delay

surface molting

lack of access to salt water

lack of a dietary calcium supplement

poor diet

chemical or insecticide exposure

rough treatment

fights with other crabs (may be due to a lack of appropriate spare shells or to a lack of protein in the diet)

Maintenance of a proper hermit crab habitat can be complicated for a beginner, but is no harder than maintaining a fish tank. Once the crab has recovered from post-purchase stress (lived for thirty days from adoption, or survived a molt or two), a careful, informed owner who controls the rest of the issues above should have his pet for a long time.

Pet stores that claim hermit crabs only live six months to one year are really admitting that they don't understand the requirements for the survival of these animals. Avoid post-purchase stress by purchasing from stores that maintain appropriate humidity and temperature in their crab tanks!

The small plastic enclosures typically sold in pet stores do not have much room and will eventually kill hermit crabs housed in them. These habitats are suitable for transportation and for isolation of sick/new crabs, but are inadequate as permanent homes.

Plastic habitats do not hold warmth well. Most of these habitats also will not maintain appropriate humidity without modification, such as affixing plastic wrap over some of the ventilation holes.

Ten-gallon aquarium tanks make good homes for very tiny (7) to medium-sized (4) hermit crabs. These tanks are big enough to hold

In addition, most ten-gallon aquariums are sturdy enough and tall enough for the amount of substrate needed for medium-sized crabs to molt. Besides glass tanks, the only good commercially-available hermit crab home is the Exo-Terra Terrarium. A full setup can be seen at the site of this UK hobbyist. The glass front doors offer easy access to the interior and make the units easy to clean. However, there are some reservations.

CAUTION: Exo-Terra brand glass terrariums are the same shape as standard glass aquariums but come with a build-in screen lid, and like glass aquariums these tanks are quite strong; however, many others are not built as strong and could break under the weight of the necessary substrate.

If using a mesh screen cover on an aquarium, one that is hinged across the width will function better than one hinged along the length. For better humidity control, a tight-fitting glass or plexi-glass lid can be used, but holes must be drilled for circulation. Some hinged glass or plexi-glass lids made for aquarium tanks have flexible plastic sections that make it easy to add air holes and spaces for cords.

CAUTION: Small hermit crabs can even use aquarium joint sealant to climb to the top of the tank, so keep the lid on tight! They are strong little animals and may push their way out to freedom. If necessary, use velcro closures or weight the top of the lid.

The depth of substrate in a habitat is critical for determining the maximum size of the hermit crabs that should be housed there (see substrate chart, below). Once the size of the crabs has been determined, the enclosure's surface area will determine the maximum number of crabs. There should be at least enough surface for 50% (75% is better) of the crabs to molt simultaneously.

Your tank should have a calibrated humidity gauge (or hygrometer) so you can keep the relative humidity within the appropriate range. This is the most important thing you can do to keep your crabs healthy. As a general rule, the humidity should never drop lower than 70%, nor should it rise above 85% at most, as crabs may smother in air that is too humid! Check for the optimum humidity range for your species of hermit crabs.

There are various ways to increase tank humidity:

extra or larger water bowls and sponges,

moistened coconut fiber backgrounds,

substrate that includes coconut fiber,

moistened terrarium moss,

humidimats/water pillows,

an automatic mister or fogger,

a humidifier and air exchanger, etc.

When selecting water bowls keep in mind that land hermit crabs can drown! A sloped or terraced entrance to the water, plus objects placed inside the water bowls like stepping stones, will help crabs to climb out and prevent drowning.

CAUTION: Do not use metal water bowls or metal mixing buckets. Rust is dangerous; heavy metals build up in hermit crabs' bodies and slowly poisons them.

Relative humidity gauges are delicate and their mechanisms can be easily jarred out of adjustment. This often happens in shipping from the place of manufacture to the retail outlet. As a result, they must be calibrated before their readings can be trusted: Hygrometer calibration instructions.

Your habitat should have both a hygrometer and thermometer positioned an inch or two above the level of the substrate. Keep in mind that the air temperature and the substrate temperature may differ. In a large tank it may be advisable to have thermometers in each corner of the tank, as the temperature may vary significantly. As a general rule, the temperature should be no lower than 22°C (72°F) and no higher than 29°C (85°F). Check for the optimum temperature range for your species.

A good way to heat the habitat is with an under-tank heater at one end. This creates a range of temperatures within the tank, so the hermit crabs can choose the location where they are the most comfortable. In some climates, an under-tank heater may not be enough alone to keep the temperature at an appropriate level. Incandescent lights may be utilized for additional heat, as well as insulating the outside of the habitat with foam panels, or simply increasing the temperature of the room the habitat is kept in.

A substrate thermometer is advisable to be sure that the substrate does not become too hot. Excessive heat could harm a buried crab or cause a uncomfortable crab on the surface to "streak" (leave its shell). A rheostat or thermostat can be used to turn the heat sources on and off as required.

Recommended substrates for a hermit crab are sand and coconut husk fiber; these may be combined or used individually. The sand should be clean masonry sand (best) or fine-grade "play" (sand box) sand. Any sand should be carefully checked for mold, insects, bits of metal or debris, or suspicious odors (bad/strange/chemical/etc). Rinse and dry the sand if you have doubts as to its cleanliness.

The sand should be deep enough (at least twice the height of the largest crab including his or her shell) for the largest crab in the tank to make its underground cave. Without a proper substrate, some land hermit crabs will delay molting and/or surface molt. Either situation should be avoided.

As an example, for a ten-gallon tank and up to medium-sized crabs (6" of substrate), one might use:

Microwave the coconut fiber for about thirty seconds to kill any mites. Then fully expand it with chlorine-free water (expect 7-8 liters). Wring out the excess water and mix everything together to a damp but not dripping wet consistency.

NOTE: Do not use wood chips (particularly not those made from any type of evergreen wood, all of which are toxic), newspaper or newsprint, synthetic fiber, or gravel. Sanitized beach sand may be used if you can locate a clean, unpolluted beach where it is not illegal to remove items.

Biting mites and other pests such as fruit flies are attracted by smelly hermit crab habitats and spoiled food. Once established, they thrive in the humid environment. Keep the habitat clean! Putting fresh food in the tank only at night will help. Mites can also be introduced by adding a new hermit crab without putting it through a quarantine period. Mites or mite eggs can be hidden in the new comer's shell.

Take prompt action if you spot an infestation in the habitat. The stress of dealing with this can cause hermit crabs to autotomize limbs, and can eventually lead to death. To eliminate mites, one should

carefully wash the tank and all the accessories in chlorine-free, highly-concentrated marine salt water or a chlorine-free mixture of water and white vinegar,

being careful to clean and vacuum out all the corners, and

setting things in the sun to dry thoroughly afterward,

replace all the substrate or bake it at 300°F in the oven for thirty to forty-five minutes to kill the mites with heat, and

optionally, introduce "predatory mites" which will eat the larvae and eggs of other mites but will not harm the crabs.

By putting predatory mites (Hypoaspis mites ) in your habitat, you could avoid a complete habitat cleaning. These mites will gradually get rid of the biting mites by interrupting their reproduction cycle. The rest of the adult mites will die of old age. The number of adult mites can be reduced by cleaning the assessories and bathing the crabs. A drawback to these predatory mites is that they will remain in your tank and you will see them there; some may find this distasteful. They will, however, prevent the re-establishment of mites in the future - just don't sterilize one of the wood pieces when you clean your tank.

CAUTION: The practice of bathing hermit crabs is currently under debate. Baths stress the hermit crabs and flush out the self-regulated mix of salt and fresh water they hold in their shells. It is up to the individual to review the facts and make a personal decision whether to bathe his or her hermit crabs, and the frequency and duration of said baths. One should at least consider bathing a crab after purchase to free it of potential mites and other parasites.

There are several ways to bathe a hermit crab. Since land hermit crabs can drown, they must either be lifted out of the water or have a way to climb out on their own. Use chlorine-free fresh or salt water at room temperature: Land hermit crab bathing techniques.

Hermit crabs also need fresh and salt water. Both types of water must be free of chlorine. Most products labeled as "hermit crab salt" are actually table salt. Proper marine salt intended for use in salt aquariums is superior and much preferred; it contains many necessary minerals not found in table salt, as well as generally being cheaper to buy than "hermit crab salt." Table salt is harmful to hermit crabs because of the added anti-caking agents and because it is devoid of many needed minerals. Oceanic, Instant Ocean, Red Sea and many other common brands of marine salt are suitable for hermit crabs: Instructions for mixing salt water.

In their search for food, wild land hermit crabs may walk many miles and climb trees every day. They may visit diverse locales such as the ocean, inland lakes, forests, meadows, marshes, etc. Captive crabs also need exercise, although they get fed regularly by their keepers instead of having to search for food themselves. They also need interaction with other hermit crabs of their own species, as they are social animals. Frequent rotation of habitat decorations gives them a change of scenery and new places to explore. Placing food dishes in elevated positions allows them to "forage."

Some individual hermit crabs seem to learn to enjoy interaction with humans. Others may be too aggressive, fearful, or physically delicate to tolerate frequent handling. Misting bottles and hand-feeding can teach "friendly" hermit crabs how to be handled. Some owners even allow their crabs to spend supervised periods roaming around their homes or yards.

CAUTION:

You will eventually get pinched. Larger hermit crabs can draw blood. Consider this when deciding to purchase a crab. They will pinch if provoked or if afraid of falling. Try to relax until they eventually let go. Misting or running warm, chlorine-free water over the crab may cause it to release its grip faster. Do not try to shake or pull them off; they will only pinch harder.

To avoid being pinched, only hold the crab by the shell ot on a flat open palm. Keep the crab away from the webbing between your fingers. Try not to irritate hermit crabs; they can hold a grudge. For example, if your crab is walking in one direction, towards a dark corner for example, do not repeatedly let it get close to the corner then pull it away again. This will frustrate it and it will be inclined to pinch you to make you leave it alone.

Children should always be supervised when handling a hermit crab.

Crabs are not insects, but are closely enough related to insects that they can be killed by insecticides. Any insecticidal sprays or compounds can potentially harm your crabs.

Hermit crabs are strong, determined little escape artists. They will get behind tank backgrounds. They will pile up on top of each other to get where they want to go, close enough to a lid to push it up. Never allow a crab to wander unsupervised outside of its enclosure.

If you want to breed and raise land hermit crabs from the egg, and are a dedicated researcher, you can join those who are trying to learn how to do so. You would have to obtain a male and female of the same species and figure out how to induce them to breed. Captive hermit crabs will normally not breed in indoor enclosures, but have done so in outdoor enclosures.

A sea water aquarium must also be provided, as fertilized hermit crab eggs are laid and hatch in the ocean. The proper temperature, nutrients, and conditions for the zoea must be determined. The baby hermit crabs, called zoea, drift freely in the ocean for the first weeks of their lives. After about two months they undergo metamorphosis into the "adolescent" megalopa stage. A month thereafter, they seek out their first snail shells and transition to life on land for the remainder of their lives.

Stu Cobb has written a copyrighted booklet on his success in raising Australian land hermit crabs (Coenobita variabilis). Photographs of hermit crabs at different stages of the life cycle and a description of one woman's efforts to breed Caribbean land hermit crabs (Coenobita clypeatus) are located at [4].

Pet stores that are not keeping their hermit crabs in proper conditions should be reported to the management. If the problem is not corrected, continue reporting that store to higher management. Remember, if nobody speaks up, nothing will change!

These are US phone numbers for reporting the mistreatment of animals:

Store

Phone Number

PetSmart

1-800-738-1385 ext. 2518

Petco

1-888-824-7257

Pet Supplies Plus

?

You can also try e-mailing them, which isn't as effective. Be sure to include the location of the pet store in your e-mail.